This invention relates to a dispensing nozzle of the type used for dispensing liquid fuels such as gasoline and the like. It is particularly directed to a compact, relatively inexpensive, and durable dispensing nozzle having an improved mechanism for latching a manually operated lever in an open position.
Gasoline dispensing nozzles conventionally include a casing having an inlet and an outlet, an outlet spout, and a poppet valve for controlling flow between the inlet and outlet spout. The poppet is urged downwardly against its seat by a spring. A valve stem, which is operated by a manually operated lever or handle, opens the poppet valve against the force of the spring. The plunger of an automatic shut-off assembly forms a pivot for the lever at the forward end of the lever.
The lever is typically S-shaped, including a forward arm pivoted to the plunger of the automatic shut-off means and also engaging the valve stem of the poppet valve, an intermediate portion, and a rearward hand-hold.
In a typical construction, the shut-off assembly also includes latching balls which are mounted in an upper portion of the plunger and are pushed outward by a latch pin against a shoulder in the casing. The latch pin includes a tapered surface which engages the balls. The latch pin is carried on one side of a diaphragm, the other side of which defines a pressure chamber with a cap on the body. A spring in the pressure chamber determines the sensitivity of the mechanism to changes in pressure in the pressure chamber. The latch pin is withdrawn from the plunger in response to submerging the end of the outlet spout in liquid. When the latch pin is withdrawn from the plunger, the balls move inward away from the shoulder; the plunger drops, thereby shifting the pivot point and preventing the lever from lifting the valve stem. This construction is well known in the art and is described in Carder, U.S. Pat. No. 3,757,834, and in Carder et al, U.S. Pat. No. 3,273,609, for example.
The automatic shut-off system of commercially available fuel dispensing nozzles drops the pivot point of the manual lever sufficiently to disable the lever from opening the nozzle's valve regardless of the position of the lever. Therefore, the lever may be held by a clip of some sort, to relieve the operator from holding the lever while a fuel tank is being filled. It has been recognized as desirable that the clip be simple, that it hold the lever securely, that it retract automatically when the automatic shut-off operates, so that the lever returns to its rest position, that it not obstruct the lever or the hand of the user in normal operation, and that it be operable with the same hand that is operating the lever. It is also desirable for the clip to be durable and relatively immune to environmental interference such as ice. The clip should also not protrude from the nozzle body or interfere with positioning the nozzle in a fuel tank or on a pump rack. Various clips have been provided in the past, but none has met all of the foregoing criteria.
A particularly popular clip is shown in, for example, Lasater, et al, U.S. Pat. No. 3,823,752. This clip is rotatably mounted to the manual lever and engages a toothed ratchet plate on the hand guard to hold the lever in a raised position. A spring, not shown in the Lasater patent, is mounted between the lever and clip to bias the clip up and out of contact with the ratchet plate. The spring is conventionally a coil spring with extended ends or else a leaf spring, although the type of spring is not essential to the operation of the clip. This type of clip releases when downward and rearward movement of the forward end of the lever causes a momentary release of the engagement between the clip and the latch plate, and the clip's spring pushes the clip up and out of engagement with the ratchet plate. This type of clip can become unreliable with use. By way of example, the ratchet plate may become worn, with resulting slippage or deeper engagement of the clip into the teeth of the plate, or the hand guard, which is frequently made of molded plastic and held by bolts to cast body of the nozzle, becomes somewhat loose, thereby spacing the ratchet plate farther from the clip and changing the geometry of the mechanism. Under these circumstances, and others, the clip may not retract when the nozzle shuts off, leaving the lever hand-hold locked in its elevated position.
Other similar approaches are shown, for example, in Carder et al, U.S. Pat. No. 3,273,609, Tamra, U.S. Pat. No. 4,593,729, and Fink, U.S. Pat. No. 6,585,014, in which the ratchet plate is held by the lever. These approaches are expected to have similar problems.
Carder et al, U.S. Pat. No. 5,067,533 attempts to solve the problem by mounting the clip on a cast hand guard and using a cast lever having a unique shape that forces the clip open when the automatic shut-off mechanism drops the front end of the lever. This arrangement is somewhat complex and costly.